The present disclosure relates to the subject matter disclosed in German Patent Application No. 101 52 797.7 of Oct. 25, 2001, the entire specification of which is incorporated herein by reference.
The present invention relates to a multilayer gasket, which comprises at least one first layer and one second layer and at least one joining device for joining the layers of the gasket to one another.
Such multilayer gaskets are known from prior art.
In particular, it is known to join the layers of a multilayer gasket to one another by riveting or penetrative jointing.
Said types of connection however lead during production of the joint to a build-up of material at right angles to the main surfaces of the gasket, with the result that the joining devices produced by riveting or penetrative jointing have to be disposed outside of the compressed region of the gasket. It is frequently necessary to provide on the layers of the gasket additional straps outside of the compressed region of the gasket in order to allow the joining devices to be accommodated in the region of said straps, which may lead to increased material consumption and to a risk of injury on account of the protruding straps.
It is moreover known to join the layers of a multilayer gasket to one another by welding. It is however not possible to use said joining method if the layers of the gasket are coated, e.g. with an elastomer, because the coating is destroyed by the welding operation. A weld joint is moreover not possible or leads to unreliable results when one or more of the layers of the gasket are formed by nonmetals.
The underlying object of the present invention is therefore to provide a multilayer gasket of the type described initially, in which the layers of the gasket are joined to one another in a simple and reliable manner.
In a gasket having the features of the preamble of claim 1 said object is achieved according to the invention in that the joining device comprises at least two through-openings in the first layer, at least one through-opening in the second layer and a joining element constructed separately from the first layer and the second layer, wherein the joining element penetrates the through-openings of the first layer and the through-opening of the second layer and engages behind a retention region of the second layer in such a way that the first layer, the second layer and the joining element are form locked, preventing them from moving apart from one another.
The underlying concept of the solution according to the invention is therefore to insert a joining element, which is constructed separately from the first layer and the second layer, through the through-openings of the first layer and through the through-opening of the second layer and then deform said joining element by upward bending, spreading and/or upsetting in such a way that a sub-region of the joining element engages behind a retention region of the second layer of the gasket in such a way that the retention region prevents the joining element from moving out of the through-openings and so the first layer, the second layer and the joining element are form locked, thereby preventing said elements of the gasket from moving apart from one another.
In said case, in addition to the first layer and the second layer the multilayer gasket may comprise any desired number of further layers, which are preferably disposed between the first layer and the second layer.
It would be conceivable for the two through-openings in the first layer to be connected to one another by a through-channel and hence form two sub-regions of a continuous through-hole in the first layer.
It is however preferably provided that the two through-openings of the first layer are formed separately from one another.
The solution according to the invention offers the advantage that no welding operation is needed to produce the joint, with the result that the joining device according to the invention may be used in particular also when one or more layers of the gasket are provided with a coating on one or both sides.
In a particular development of the invention it is provided that the joining element comprises at least one strap, which is deformed into the plane of the second layer.
It is particularly advantageous when the joining element comprises at least two straps and a middle region disposed between the straps.
In particular, it may be provided that said middle region is received in the through-opening of the second layer of the gasket.
In a preferred development of the invention it is provided that the middle region of the joining element lies adjacent to a web formed between the through-openings of the first layer.
With regard to the arrangement of the retention region, it is particularly advantageous when the retention region of the second layer is deformed out of the plane of the second layer into the plane of the first layer or into the plane of a layer of the gasket disposed between the first layer and the second layer, should the gasket comprise at least one further layer in addition to the first layer and the second layer.
To prevent the arrangement of the joining element on the gasket from leading to a build-up of material in the region of the joining device, it is advantageous when at least one surface of the joining element is substantially flush with a boundary surface, i.e. with a top or bottom cover surface, of the gasket.
It is particularly advantageous when an upper side of the joining element is substantially flush with an upper side of the gasket and an underside of the joining element is substantially flush with an underside of the gasket.
It is preferably provided that the joining device is disposed in a region of the gasket which, in the installed state of the gasket, is compressed.
This is possible particularly when the joining device is constructed in such a way that it does not form a build-up of material beyond the boundary surfaces of the gasket.
As a result of the arrangement of the joining device in the compressed region of the gasket it is possible to dispense with additional straps at the external contour of the gasket, which are otherwise provided for the arrangement of the joining devices. A spin-off effect of this is that the external contours of the gasket do not project beyond the components to be sealed, thereby lending a more pleasing shape to the component group formed by the gasket and the components to be sealed.
The risk of injury posed by the projecting of the external contours of the gasket beyond the components to be sealed is moreover eliminated.
Further features and advantages of the invention are the subject matter of the following description and the graphic representation of an embodiment.